What are some of the applications you have used a circuit breaker for?

132 answers

Answers:

I finally started construction work in 1951, switched a couple of contractor and was involved with all Brands and all types of Cir. Breakers, in commercial Buildings, Power plants, Reactors, Dorms, Hospitals, Factories, Stadiums, Switch yards, and you name it. I had a good enjoyable life in the Electrical Construction field.

I run coordination studies for power plants / industrial customers. Not only to properly coordinate a system, but also to mitigate HRC levels. Many times I must recommend replacing breakers to properly coordinate so some design aspects are used. I am also involved in testing breakers, usually on shutdowns by the customer.

~Engineering, Other, Ashland, MA

1.Now I am working as a design engineer and I use MCBs, MCCBs & ACBs in LV panels.
2.When I worked in VCB manufacturing plant, I involved in testing of VCBs
3.When I worked as a Substation Commissioning engineer, EHT CBs were used.

~Sreejith V, Design Engineer, Kannur, India

For all types of protection on MCC up to 5.7 MVA distribution system protection on 80 MVA Transformers step down to 230kv to 34.5kv and circuits of step up up to 100 mva from 4,16 to 13.8kv other generator protection on LSIG and ark protection on MV bus section etc.

~Syed Moheed ALi SMA, Design Engineer, Jubail, KSA

I design and build switchgear. Most of the time, the circuit breakers are used as an over current protection device, though sometimes we use Square D breakers as a means to hold open doors that tend to drift closed.

Please share with us any “non-standard” applications that a circuit breaker has been used for.

28 answers

Answers:

D.U.R.T. Very fast circuit breaker based on Thomson effect technology. This circuit breaker has been made to be installed on low voltage switchboard with a very short circuit withstand, Opening time < 5 millisecond.

~Jean Bozonat, Project Manager, St Hubert, Canada

480 4000 Amp fuses acting as a main protection for multiple lineups of switchgear. The trip curve on the 4000 Amp fuses allowed extensive damage to the LV switchgear when a fault occurred.

~Mike V, Marketing/Sales, Tampa, FL

Emergency Power Off Switch. We use a low voltage release to trip the Main Disconnect when an EPO switch is activated dropping the loop to the low voltage switch.

There are hundreds of stories out there, most are caused by Human error. Be sure that a Qualified Individual is installing and energizing your equipment. In other words, don't let somebody's brother in law who "Knows a little bit about electricity" install. Recommend or work on your gear to save a little bit of money. If in doubt, call me at Coastal Power Systems and I or someone else can help you with your needs.

~Colin K, Sales, Design and Production, Houston, TX

Yes. I've seen the result of an owner not replacing a circuit breaker and wire when they have replaced a pump motor with a larger horsepower motor than was originally installed. Cost them more the second time than it would've if they'd done it right the first time of replacement.

~Warren C, Senior Electrical Designer, Columbus, OH

If you don't select the breakers with the correct short circuit rating and settings are not properly set in the trip unit, then it will not trip under abnormal condition. It will damage the electrical load which is connected with it.

~Siva Chandran, Design Engineer, Bangalore, India

Thermal CBEs are sometimes used as protection against short circuit, and the majority of these devices are not fast enough to prevent damage occurring. It is very important to know what you want to protect against and choose your protective devices accordingly.

~Mark P., General Management, Sevilla, Spain

Yes, many OPEX-s (operational experiences) are recorded and shared within the Nuclear Industry which are - I believe - also accessible for the public through the Internet. (Some of these are recorded accidents and their full stories, lessons to be learned...etc...)

~Thomas U., System Engineer, Clarington, Ontario, Canada

Not personally, but potentially serious destruction of life and property could occur if incorrect selections are made. Circuit breakers are there to protect cables and equipment so that their ratings are not exceeded.

~Tom R, Builder/Contractor, Princes Risborough, England

Yes, it was due to human mistake. Metallic tool kept inside the circuit breaker after completing the PM. Breaker was racked-in service position then severe flash over occurred.

~Khalid Al-Zelaibani A, Engineer, Yanbu, Saudi Arabia

During a problem of Breakers not tripping in the proper sequence finally ending up taking our a 480Volt- 2000 amp switchgear unit which started from a 20 amp breaker failure to trip in a secondary panel.

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